1. Field of the Invention
The present invention relates to a device and a method for controlling a temperature of a soldering iron tip, and in particular, a device and a method for controlling a temperature, which achieve excellent temperature controlling characteristics with only simplified circuits.
2. Description of the Related Art
For example, a U.S. Pat. No. 5,043,560 has already been known as a method for controlling the temperature of a soldering iron tip, that is, a soldering tip. The invention varies a period of current flow of a soldering iron in a range from 0% to 100% in half the cycle of alternate current voltage, wherein a technology called a pulse width controlling system has been employed. As a rule, it is considered that the invention is excellent in its following ability since the temperature is controlled once every half cycle (H.apprxeq.8.3 mS).
However, the present inventor examined and confirmed that even though the temperature is controlled once every several milliseconds, there is almost no difference in capacity between in the above case and in a case where the temperature is controlled once every tens of milliseconds, and control adaptive to a thermal response property of a soldering iron tip is sufficient.
Further, where a pulse control system is employed as in the above invention, since waves are generated in such a shape as shown in FIG. 6 in response to the temperature of a soldering iron tip, voltage supplied to a heater is instantaneously switched from an OFF state to an ON state, and high frequency noise is generated. The nearer the current supply term (H-T) is to H/2, the more remarkably the high frequency noise becomes. Provisionally, even though a direct current voltage is supplied to the heater, the high frequency noise cannot be improved as far as a pulse width controlling system is employed.
Still further, the U.S. Pat. No. 5,043,560 has a complicated circuit configuration to achieve the invention, and, moreover, only simple performance can be displayed. Therefore, there remains an unsatisfactory point in the controlling capacity with respect to commencement and pause of operations.
The present invention was developed in view of the above shortcomings and problems, and it is therefore an object of the invention to provide a device and method for controlling a temperature of a soldering iron, which achieves excellent controlling capacity, with only simplified circuit configuration.